Means for determining the normal occlusal plane



March 19, 1929. c, o, MCBEAN 1,706,179

M MEANS FOR DETERMINING THE NORMAL 'OCCLUSAL PLANE Filed May 2:5, 192'!s Sheets-Sheet 1 INVENTOR) aamamn;

ATTORNEY 19, 1929. c, Q MCBEAN 7 1,706,179

MEANS FOR DETERMINING THE NORMAL OCCLUSAL PLANE Filed May 23', 1927 3Sheets-Sheet 2 ./0 T llllll INVENTOR,

ean;

T ORNEY Patented Mar. 19, 1929.

UNITED STATES CHARLES O. MCBEAN, OF LOS ANGELES, CALIFORNIA.

MEANS FOR DETERMINING THE NORMAL OCCLUSAL PLANE.

Application filed May 23,

This invention relates to the science of producing partial or completeocclusive masticatory elements. I

The old system of preparing dentures is to first make a cast of upper,or maxillary ridge, and then, lower or mandibular ridge, then buildingof base plates to the casts and then bite blocks are built upon the baseplates.

A try for esthetic plane is made by arbitrary guess according to the lipplane and facial expression.

Thus no regard is given to the actual masticatory plane on which maximummuscular forces are registered.

It is the interpretation of practitioners that they can determine theproper plane by the mandibular condyle path. Thus working from anunsound basis to doubtful registration.

lVith the base plates and their bite blocks seated in the mouth thecondyle path, in a given case, is determined by taking three bite platesof plastic wax, one for a right lateral, one for a left lateral and onefor a protrusive.

After the bites have been taken the mounted bite blocks are brought intocentric occlusion and sealed together.

Now a face bow tongue is fastened rigidly to the sealed blocks afterwhich the face bow lugs are adjusted to the head of the condyles of thepatient. Having located the head of the condyle, then the stem of thetongue is set to the face bow. The face bow and set bite blocks are nowremoved from patient and the lugs of the face bow are mounted upon thecondyles of the articulator. The casts or models are now seated in theirrespective base plates which are held by the bow, then the casts aresealed to the bows of the articulator.

Following this the face bow and its tongue are remo *cd from the biteblocks and the articulator. Then the condyle paths established on thearticulator by registering the casts with the previously taken bites andfrom and by this mechanically determined and delimited means thearbitrary occlusive )lill'le of the teeth is produced as tooth aftertooth is placed in position on the base plates following the removal ofthe bite blocks.

The occlusive plane so produced is usually so erroneous that either spotgrinding by the prosthetist is resorted to orthe teeth are graduallyabraded into the correct occlusive 1927. Serial No. 193,539.

plane by chewing on carborundmu-filled gum.

Many deleterious effects are common as a result of the use of denturesmanufactured by the above apparatus. Such for instance; as pathologicchanges in the condular articulation; aggravated and uneven obsorptionof the bony processes, together with a defic1ency of function of thedentures, all caused by an utter disregard for the muscular forcesinvolved in mastication.

The apparent error in the old system is that the mechanical articulationis not founded upon such a basis as will result in the true coordinationof all of the occlusive surfaces in coordination with the muscularforces involved in a given case.

The ideal is the reconstruction of the masticatory mechanism in such amanner the the entire masticatory apparatus is functioning in perfectharmony with the muscle forces applied.

This, therefore, involves the coordination of action of the condulararticulation, and the coaction of the occlusive surfaces of themasticatory mechanism upon the plane of maximum force functioning inharmony with the muscle forces applied.

Failure of coaction of the upper and lower articular surfaces,throughout, results in traumatic occlusion which is likely to producepathologic changes in the tissues of the condular articulation, orpathologic changes in either the soft or hard tissues of either, orboth, the mandible or maxilla. his condition will result in a partial orcomplete loss of elliciency of the masticatory mechanism.

It is recognized that it is of the utmost importance to provide anedentulous patient with a set of dentures which will effect arestoration of the natural appearance, will be successful in theirintended function and give general satisfaction in a comfortableapplication on the gums. In the attempt to produce a reasonableil-pplfiiil'll to the normal condition of the case the practitionera aredivided in two general principles: one is that the condyles constitutethe controlling media of masticatory procer s and the other is thatocclusion conti the condyles, this latter being known as the sphericalprinciple.

I submit that these principles are quite secondary and that thefundamental basis of rnasticatory balance and efficiency is Ill) thecoordination of the heavy muscles, es-

' termine the occlusion plane normal to the CID Cil

teeth.

There is no doubt that there is an ideal occlusion plane for everyindividual masticatory system and it is undeniable that there is amasticatory planenormal only to each individual and for this reason ofthe posi tive difference in the conditions in every case, that it isimpossible to use a mechanical articulator with delimited lines ofcondular movement to accurately adapt artificial teeth whose occlusialsurfaces are the product of the limited action of an articulator.

The condyles of the mandible-are known to have a practically universalfloating action under the mastoid process and there is little or nolimit to the gyratory motion of the condyle in any definite plane suchas is assumed by' the use of the usual articulator. The mandible isunder the control of a complex system of muscles whichin the action. ofmastication cause the condyles to work in a loose floating manner whilesupported on the mastoid process, the points of support of the condylesvarying constantly during the movement of .t-he'condyles at least untilmaximum crush effort of the coordinated muscles brings the condyles tothat indefinite and variable seat as will be de-' ,muscles.

Knowing that the mandible will have its condyles adjusted as determinedby the reaction of the bolus and the tension of the mastic-atorymuscles, it is the cardinal object of my present invention to providemeans adapted to be adjusted in the oral cavity while said means are insitu on a supporting means which has been previously carefully adaptedto the upper and lower gumridges of the maxilla and the mandible withthe object in View of utilizing the fitted supports which are toultimately carry the false teeth combined with means to accuratelydetermine the true normal occlusion plane in each individual case wherepartial or complete dentures are to be installed. In other words it isan object of my present invention to provide a system including meansadjustable in the oral cavity to nicely determine the plane of occlusionin a case, while carrying out the desired line of csthetics, which inthe general present practices of the profession of prosthesis is thearbitrary line assumed for the building up of dentures, with the objectof bringing the face into an apparently normal state of rest and at thesame time supposedly to result in a fair adjustment of the occlusionthrough the mechanical instrumentality of the conventional articulator.In attempting to produce dentures froin the arbitrary line of estheticsin conjunction with the use of bites, no consideration whatever has beengiven to the h1ghly important factor of muscular actions and it is apurpose of my invention to directly consider the actions of the muscleson the mandible in erecting either partial or full dentures with thepurpose in view of giving to the individual dentition means which havebeen produced with consideration of the factors of esthetics,

of condyle action of a normal occlusion plane and-of the combinedactions of the principal muscles of the masticatory system.

A further obpect of the invention is to provide a system of deviceswhich .arec'apable of being adjustably attached to denture plates as maybe necessitated according to the undulations and angularitics of the gumridges or gum ridge the case may 0 be. An object is toprovide a smalland practicable means capable of being'e'asily attached to a fittedridge element, such as a plate or partial plate and which includes meansadaptable for angular adjustment so that the ideal and normalmasticatory plane for the proposed teeth or tooth may be accuratelyascertained directlyfrom data established by the refined adjustment ofthe plane finder in the oral cavity.

Numerous additional objects, advantages and features will be mademanifest in the ensuing specification of an embodiment as herewithillustrated; it being understood that modifications, variations andadaptations may be resorted to within the scope,

spirit and principle of the invention as more particularly hereinafterclaimed. 7

Figure l'is a side elevation of a portion of a human skull to indicatediagrammatically the normal plane of contact of teeth in the mandibleand in the maxilla and showing the spacing of the condyle from thesuperadjacent fulcrum or the condylar foramen of the condyle andindicating in a general way the lines of forces of several of theheavier muscles just abovementioned.

Figure 2 is a front elevation of the mandible with its condyles spacedbelow the condylar foramen; and indicating by converging lines thedesired balance of force on each side of the mandible with respect tocertain predetermined teeth.

Figure 3 is a plan of the mandible with full. dentition.

Figure 4 is a plan of a lower ridge fitter denture plate illustratingthe attachment, in

clusion plane finders.

. Figure ,5 is a front elevation of upper and balanced relation. of aset of the novel orlower plates showing a pair of right and leftbalanced plane finders applied.

Figure is a side elevation ot upper and lower plates showing appliedplane finders.

Figure? is a front elevation of an individual plane finder as attached.

Figure 8 is a side elevation of an individual plane iinder.

Figure 9 is a detail view showing the method of obtaining a record ofpressure developed under muscular action in bring ing opposed planefinder platens into occlusion.

Figure 10 is a plan of a pressure receiving pan.

.Figure 11 is an enlarged sectional view of the pan.

Figure 12 is a front elevation of a detached platen with its jackscrews.

Figure 13 is an end view of the plate.

Figure lei is an elevation of the platen clamp screws.

Figure 15 is a bottom plan of the platen.

Figure 16 is an elevation of the detached platen jack screw.

Figure 17 is a plan of the jack screw.

Figure 18 is a front elevation of a platen carrying bracket.

Figure 19 is an elevation of a bracket clamp screw.

Figure 20 is an end view of the bracket.

Figure 21 is a top plan of the bracket.

'Figure 22 is a top plan of the bracket cradle.

Figure 23 is an elevation of the cradle rock-shaft.

Figure 24 is a front end view or". the cradle.

Figure 25 is a side view of the cradle in cluding its adjusting screws.

Figure 26 is a top plan of the main clamping device or bed of thefinder.

Figure 27 is a front end view of the bed.

Figure 28 a side elevation and partial section of the bed showing one ofits clinching screws.

Figure 29 is a side elevation of an opposed pair of platens havinground-ed occlusion surfaces.

Figure 30 is an end view of a platen having a concaved occlusionsurface.

Figure 31 is a perspective of an occlusion surface cutting knife.

Figure 32 is a detail showing an occlusion linite in eilcctive positionagainst a prepared and protected upper occlusion platen faced with amodelling compound on which the ultimate impression tor occlusion isimpressed.

Figure illustrates a pivoted impaling hook.

Figures 1, 2 and 3 are introd ced to show very closely the actualrelation of the condyles C to the superad acent bony structure formingthe tulcra F in a case taken directly from a. dry skull in which therewas usually complete and perfect set 01'? upper and lower teeth. Figure1 illustrates the actual position of the condyles 'hen the teeth of theskull were in what appeared to be the normal plane of occlusion when allot the teeth were brought into the ideal and normal re ster. Thisexample clearly demonstrates that in human cases having an idealmasticatory plane the condyles take positions which are determined bythe lines of occlusion of the teeth. It is obvious that the surfaces ofthe teeth will be worn to planes which are determined mainly directlyfrom the final coordination of the heavier muscles utilized in theprocess of mastication and which muscles are illustrated in Fig. 1, in amore or less general manner by the heavy dotted lines.

My present system for determining a normal occlusion plane to each indi'idual case is based on the fundamental principle that aside from habitsand possible abnormalities the planes. of occlusion especially to be determined for full dentures will best be arrived atby a means capable ofbeing adapted in each case to the peculiar conditions resultant from themain muscles of mastication in each given case. lVhilc it is highlydesirable to follow the principle involving the line of esthetics andwhile it is also desirable to give due consideration to the socalledspherical principle and to the theory that occlusion is primary as afactor I believe that a most satisfactory result including the comfortof the patient depends upon the development of the given case almostwholly by a means which will give the patient a line of occlusion indirect conformity to the lines of forces generated and concentrated bythe concurrent and true coordination of the masticatory muscles, in thegiven case.

In a given edentulous case the dentures should be developed by meansworking from equalization of forces on the mandible M. Figs. 1 and 2, asfor instance, by determining that position of the mandible when it isunder the contracting force of muscles which would set the lower cuspidsand the first molars in esthctic balance at the moment and position whenthe muscles are exerting their maximum etl'ort.

With the object oi? most easily and accurately obtaining the ideal andnormal occlusion plane for a given case it is assumed that upper andlower denture plates U, L have been obtained in the usual manner. Tothese plates it is possible to attach means by which the true planes ofocclusion can be arrived at and my invention consists in means which arenot only attachable to the prepared plates or partial plates but suchmeans further includes parts adjustable laterally, angularly andvertically so that an U11- the mandible an be carefully brought to thatdesired position of closed occlusion surfaces at which all of thefactors involved in mastication are so truly coordinated that thepatient may have the comfort given originally by his normal teeth.

The mechanism of the invention includes a main carrier, frame or bedpart 2 made of any suitable material and of various sizes and whichincludes forwardly or outwardly extending side arms 3 and rearwardly cxtending arms a which arms are severally provided with screw holes 5 allpitching obliquely inwardly as. clearly shown in Fig. 28 to receivesubstantial clamping screws 6, which form one means by which the bed 2may be applied firmly to the ridge fitting plate or partial plate U or Las the case may be and which screws are shown as having sharppenetrating tips 7 to readily bite into ing the cradle on the bed. Thecradle 10. has

screw holes 13 into which turn clamp screws 14, Fig. -19, and these passthrough a slotted base of a bracket 15 having an upstanding'wall 16, thelower portion of which is concaved at 17 for a purpose later shown.Therefore, the bracket 15 is capable of being adjusted laterally as tothe cradle 10 in any position of the cradle on its bed 2.

' The bracket wall 16 nas screw holes 18 to receive clamp screws '19,Fig. 14;, passing into slots in what is here termed the plate 20, whichincludes a top or shelf poirt-ionand a perpendicular medial flangeportion 20 which is provided with a threaded bore to receive astoutscrew 21 forming a jack for solidly supporting and for adjusting theplaten 20 with respect'to its bracket 15; the head of the jack screw 21turning free in the recess 17 of the bracket.

The arms 3 and a are designed to permit of being bent so that the bed 2can be set hard down on the ridge of the denture part or plate and thenclamped by the clamp means here shown as the screws 6. this beingdesirable because of the irregularity of the denture part as determinedby the ridge of the gums of the patient being fitted.

In the technique of the system a pair of upper and lower posteriorfinders is set at approximate relation to lateral and height positionsat which time the lateral position is correctedby ad ustment of theocclusion ,ing in temporary height adjustment.

platens which are brought into flat or co ordinate contact with themandible in centrio occlusion; the planes of the platens be- The platensare now set at low points or a closed bite relation and a pressurerecord is made by suitable means which is here shown as-including asmall, compressible,hollow disc or pan attached to the end of a flexibleconduit 31, of any suitable type or construction and material, and whichextends to a fixedly mounted reservoir 32 which is provided ith anindexed or scale tube 33 in which is visible the movement of a liquidcontained in the pressure pan 30 and its conduit and reservoir. For thepurpose of making a pressure test the pan 30 is introduced between thebase of the upper jack screw Fig. 9, and its cradle 10 while theocclusion platens of the upper and lower plates are in occlusion. Thepressure exerted by the bite of the patient is determined from thepressure pan 30 by the expulsion of liquid therefrom and a consequentchange of level of the indicatliquid in the index gage 33, which iscalibrated with a range of index readings predetermined as being theaverage between a very low pressure to a very high pressure under.muscle action.

Following the first test or extreme posterior position the platens ofthis set are adjusted at an open bite relation and pressure is taken andrecorded and subsequently readjustment'of the platens is made and bitesand pressure readings are completed until the plane of maximum pressurefor the trial sets of platens is ascertained. words the first sets ofplatens for upper and lower plates are set arbitrarily as close aspracticable to the line of esthetics and thereafter the upper and lowerplatens are equally adjusted for closed bite relation and record ofpressure and then equal adjustments of both upper and lower arecontinued until the maximum pressure recorded in the different stepswill determine that occlusion plane normal to the case.

in Fig. 4, a set of four of the plane finders is applied in balancedrelation to a ower plate and after the tests for pressure have beencompleted with the set of four finders on'.-upper and lower then thereapplied to the upper and lower plates additional finder sets to completethe occlusive line entirely around the plates.

After the proper occlusion plane has been ascertained at which maximummuscular energy is effected, both as to gum reaction and to condulararticulation, then the platens 20 are removed from the lower finders andthere is applied to the lower brackets 20 a suitable cutting knife orblade 22, Fig. 82, the effective cutting edge of which is adjusted to aliue'above its cradle 10 as In other determined by the previouslyascertained height of the top or" platen from the cradle. There is thenapplied to the articular surface of the upper platen 10 a modelling compoun l. Knives having been adjusted to each of the lower cradle bracketswhile the upper platens remain in place, then the patient is instructedto proceec to chew in the normal manner. \Vhen the blades 22 have outthrough the modelling compound to the articular surface of the upperplat-en 20 the id and normal occlusion plane has been established in thegiven case.

After this the prosthetist carefully replaces the occlusion findingmeans on the lower plate by false teeth in the following manner. Thepatient is instructed to close the jaws in centric relation and thelower knives are sealed to the now out oeclusal plane as determined bythe carvings, after which a face bow transfer is made or" the sealedupper and lower base plates to an articulator which is capable of thescope of movement recorded upon the compound on the upper platens.

ll ith position No. 1, Fig. l, as a starting point in a plate in thearticulator a series of porcelain teeth is selected, due regard to typeand size, and these are eac preground on their occlusal surfaces toarticulate closely with the establisiied occlusion planes on thearticular surfaces of the opposing upper platens and are then set on thelower )late ridge and attached by wax. The ground teeth are setprogressively around the arch, each being carefully brought into properangular position. Then the top or upper plate is completed by a similarprogressive mounting of the teeth from one end around to the other onthe upper; and the attachment of the teeth to the base plates producedin permanent form, giving a in: icatory plane in harmony with theion-cos of mastication.

Figure 33 shows a form of pivoted claw or 1o l: 6 having a jamb screw (5on one arm whereby to obtain a secure iinpaling grip on the plate face.

What is claimed is:

1. The combination with a denture plate, of an adjustable l ed, andmeans on the bed for obtaining the masticatory i ud a be:L adjustablyattachable to ridge F t ng member, and means on the b adapted foradjustment to the relative and having a plane finder.

including neans chimp onto the said parts, a tilta is member mounted onsaid means, a laterally adjusta- I rent on said member, and a platen oleon the said element. 0. sin occlusal plane finder including a basemeans. means to attach the base to a rido e fitting; denture part, acradle tiltably led on the base and means to set the "ustnient, alaterally adjustable bracket e cradl and means to set it in ad' on, andplaten adjustable on the bracket and means to positively set the platenwhen it has been adjusted.

K us for finding the normal oeme in a given case, including upper andlower means adjustably attached to respective ridge fitted parts, one ofsaid means being adapted to form a base for a modelling compound and theother having a knife operative to cut a mas icatory plane on the opposedcompound.

7. The method of locating the normal niasticatory plane which consii tsof fitting rum plates, ascertaining the occlusion plane by effecting pive angle position of the mandible at rent bites, obtaining pressurereadings at different positions of the mandible, and settin the teeth onthe plates in accordance with the ascertained plane of 1 um pressure. a.in combination with L. .L ilii upper and lower plates, a base adjustablymounted on one or said plates for a modelling compound, and cuttingmeans adjustably mounted on the opposed plat to cut a masticatory planeon the compound.

CHARLES O. MoBEAN.

